1. Field of the Invention
The present invention relates to a catheter and drainage system and more particularly to improvements therein whereby bacterial intrusion into the system is effectively barred.
2. Prior Art
As is well known, the patients who have suffered from cerebrospinal diseases such as cerebral hemorrhage, softening of brain or spinal injuries, tend to be afflicted with dysuria of incontinence of urine. It is therefore necessary in such instance that a urinary catheter be inserted into the urethra and retained in the appropriate position for urination for such patients as well as for those who have undergone various surgical operations. Such catheters are often called "indwelling catheters," which must be sufficiently mechanically soft and resilient for effective use.
While the indwelling catheter is retained in the urethra for a relatively long period of time, it would permit pathogenic bacteria attached to the anus or genital vulva to enter through the urethra into the bladder, thereby frequently causing cystitis, urethritis, or pyelitis or the so-called "ascending infection." This is pronounced particularly with female because her urethra is wider, shorter, and more linear than that of male.
Various attempts have been made to prevent the bacterial infection during the use of such indwelling catheters. One such attempt has been to coat the catheter with an ointment containing an antibiotic or bactericide. Another attempt has been to irrigate the bladder through the catheter and wash the catheter at frequent intervals, and at the same time to administer the patients with antibiotics for prophylactic purposes. These proposals, however, are tedious and time-consuming, and are not completely free from renewed invasion by pathogenic bacteria.
Indwelling catheters are nowadays used in combination with urine drainage devices of either an open-circuit or closed circuit design. The closed drainage system has been preferred to delay infection in patients with long-term urethral catheterization by virtue of its isolation from the ambient. Reportedly, however, more than 60 percent of the patients catheterized in closed drainage systems are infected within about seven days due to intrusion of bacterial from between an exposed portion of the catheter and the mucous membrane of the urethra, between the catheter and the drainage tube, or from the outlet of the urine collecting bag.